AB0877 Quantification of the enthesic response to biological therapies in patients with spondyloarthritis by computer analysis of ultrasound images.
Authors: M. Tortosa-Cabañas, C. Guillén-Astete, Á. Andreu-Suárez
Journal: Annals of the Rheumatic Diseases (2022)

Background Enthesitis is the base of the pathophysiology of spondyloarthritis. Recently, our group has shown that computer analysis of static images can be used in the evaluation of patients with enthesic inflammatory diseases with good intra-patient and intra-observer validity and sensitivity to change. Objectives To determine the enthesic evolution in patients with spondyloarthritis (SpA) treated with three different biological therapies through the computer analysis of ultrasound images. Methods We selected patients diagnosed with SpA and enthesitis followed by imaging, who started biological therapy with a TNF inhibitor, an IL17 inhibitor or an IL12/23 inhibitor. For the records to be included, it was necessary to have clinical information from the period of perfoming the ultrasound. All images were obtained from the Achilles tendon, with the same ultrasound equipment, grayscale and settings for each patient. To homogenize the results of the analysis, the gray intensity mean index (iMIG) was used, which has been shown to appropriately discriminate the inflammatory pathology from the mechanical or healthy controls as well as being sensitive to change. Results 14 patients were included: 6 treated with a TNF inhibitor, 4 with an IL17 inhibitor and 4 with an IL12/23 inhibitor. Patients 2, 3, 5, 7, 10, 11, and 12 had enthesophytes. In the global analysis, the iMIG did not show statistically significant differences between the treatment groups at the start of the treatment, at the intermediate and at the final evaluation (P=.588, .739 and .674, respectively). Patients with enthesophytes presented significantly higher baseline, intermediate and final iMIG than patients without them: 1.26 SD 0.14 vs 0.85 SD 0.05 (t=7.407, P=.001), 1.24 SD 0.15 vs 0.97 SD 0.1 (t=3.659, P=.006); and 1.21 SD 0.12 vs 1.05 SD 0.07 (t=2.342, P=.037), respectively. Analyzing only the patients without enthesophytosis, the final iMIG showed statistically significant differences between the 3 administered treatments (ANOVA, F=8.142, P=.027), being relevant between the use of IL12/23 and TNF inhibitor in favor of the former (Bonferroni, P=.03). In the same subgroup of patients without enthesophytosis, iMIG analysis over time showed statistically significant differences between final and baseline iMIG (Friedman -1.938 P=.000). Conclusion Computer analysis of ultrasound images using the iMIG distinguishes therapeutic response in patients without enthesophytosis. The interposition of enthesophytes impede the correct visualization of the enthesis and does not allow ultrasound changes to be detected in some areas of the image. Although there are indications that the use of this analysis could also predict the behavior of certain therapies, it is convenient to propose prospective studies with homogeneous ultrasound controls. Table 1. List of patients included in the analysis. After the final ultrasound examination, the follow-up time up to the present is recorded in the case of continued treatment (m: months). Treatment Enthesophytes Basal MIG Basal iMIG Intermediate examination Intermediate iMIG Final examination Final iMIG Treatment follow-up 1 TNFi 71,424 0,85 +6m 0,89 +6m 0,94 Continues +24m 2 TNFi + 156,415 1,48 +5m 1,51 +6m 1,52 Suspended for inefficacy (enthesitis) 3 TNFi + 164,323 1,32 +6m 1,34 +6m 1,35 Suspended for inefficacy (enthesitis) 4 TNFi 69,321 0,78 +4m 0,80 +6m 0,94 Suspended for inefficacy (axial pain) 5 TNFi + 141,473 1,14 +6m 1,19 +4m 1,18 Suspended for inefficacy (enthesitis) 6 TNFi 68,483 0,85 +3m 1,03 +5m 1,05 Continues +20m 7 iIL17 + 135,432 1,34 +5m 1,26 +4m 1,15 Continues +22m 8 iIL17 72,225 0,90 +6m 1,02 +4m 1,06 Continues +20m 9 iIL17 80,465 0,89 +3m 1,03 +6m 1,03 Suspended for inefficacy (arthritis). 10 iIL17 + 122,254 1,16 +6m 1,11 +4m 1,04 Continues +24m 11 iIL12/23 71,401 0,79 +8m 1,01 +4m 1,1 Suspended for inefficacy (axial pain) 12 iIL12/23 + 134,41 1,12 +6m 1,08 +6m 1,07 Continues +18m 13 iIL12/23 75,42 0,94 +4m 1,12 +6m 1,16 Continues +20m 14 iIL12/23 69,112 0,84 +3m 0,9 +8m 1,12 Continues +18m Disclosure of Interests Marina Tortosa-Cabañas: None declared, Carlos Guillén-Astete Speakers bureau: Novartis, Janssen, Abbvie, Grunenthal, UCB and Gebro, Paid instructor for: Roche, Novartis, Janssen, Esteve and Menarini, Consultant of: Janssen, Novartis and Roche, Grant/research support from: Pfizer, Grunenthal, Gebro and Novartis, África Andreu-Suárez: None declared